If you think you’re especially bad at handling uncertainty or ambiguity about the future (and almost everyone is pretty bad at that), you’re probably right — and it’s potentially because of your brain. New research out of Dartmouth College has found that low tolerance for uncertainty is associated with an unusually large striatum, a part of the brain primarily associated with motor function, but also shown to be associated with reward assessment in animal studies. In an interview with Psych Central, lead researcher Justin Kim explained:
The striatum encodes how predictable and expected a reward is … Given that an important component of intolerance of uncertainty is a desire for predictability, our findings offer a biological marker related to our need for predictability.
For their study, researchers had 61 students fill out a questionnaire designed to assess their ability to manage uncertainty surrounding the possibility of future negative events. The students then underwent MRI scans, which were subsequently examined by the researchers. What they found was that the volume of the student’s striatum was significantly associated with intolerance of uncertainty — in other words, the lower the tolerance, the bigger the striatum. (Just like I always say.) While previous studies have found a positive association between striatum size and the presence of generalized anxiety disorder and/or obsessive compulsive disorder, this study is notable for isolating just one of the symptoms commonly suffered by people with those disorders (intolerance for uncertainty) and establishing its association to an enlarged striatum. Thus, a person with an enlarged striatum may well be less tolerant of uncertainty, but will not necessarily qualify as anxious or obsessive-compulsive.
The researchers suggest that because the results were observed in healthy individuals, the presence of an enlarged striatum might predict the risk of developing anxiety or OCD later in life, but emphasized that further research is needed. In the meantime, try not to worry too much about how little we know for sure.